Put the flax seeds into a bowl and mix with the water. Set aside for 10 minutes until jellified
Put the drained black beans into a medium-sized bowl, add salt (optional), lime juice, lime zest, the spices, and 2 tbs of olive oil. Using a fork, combine the ingredients
Add the flax mixture and coriander leaves and combine, Leave to stand for 10 minutes
Shape the mixture into four patties.
Put the remaining oil into a frying pan over a medium heat. When the oil is hot add the patties and cook for 5/7 minutes each side until golden briown
Serve immediately with a burger bun and salad